For high pressure pumping applications, torque is often transferred to the pump by a shaft passing through a packing. The packing has a tendency to leak (sometimes this is planned) and is difficult to maintain. The elimination of the packing is, therefore, highly desirable. Three prior approaches to the elimination of the packing have been electromagnetic induction drives (i.e., "canned" motors), permanent magnet induction drives, and inner and outer permanent magnet drives. In some of these approaches, great emphasis has been upon the circulation of the fluid being pumped into and out of the rotor chamber to provide cooling and lubrication. They have also been designed to provide a measure of thrust balancing to avoid the use of thrust bearings. The implementation of these approaches have been complex. At least partially due to the complexity of the construction, the pump has often involved at least three gasket-type high pressure seals that require proper compression to maintain the seal.